1. Field
Exemplary embodiments of the present invention relate to a semiconductor memory technology, and more particularly, to a variable resistance memory device and a method for fabricating the same.
2. Description of the Related Art
A variable resistance memory device stores data using a variable resistance material that switches between different resistance states depending on a supplied voltage or current. Currently, various variable resistance memory devices such as ReRAM (Resistive Random Access Memory), PCRAM (Phase-change Random Access Memory), FRAM (Ferroelectric Random Access Memory), and MRAM (Magnetic Random Access Memory) have been developed.
FIG. 1 is a cross-sectional view illustrating a conventional variable resistance memory device.
Referring to FIG. 1, the variable resistance memory device includes a bottom electrode 10, a top electrode 12 and a variable resistance material layer 11 interposed therebetween. The variable resistance memory device may be fabricated by a series of processes of forming a bottom electrode 10 over a substrate (not illustrated) having a predetermined lower structure formed therein, depositing a variable resistance material on the resulting structure having the bottom electrode 10 formed thereon, forming a variable resistance material layer 11 by selectively etching the deposited variable resistance material, and forming a top electrode 12 over the variable resistance layer 11.
However, during the etch process for forming the variable resistance material layer 11, the sidewalls of the variable resistance material layer 11 may be deformed by an impact. In this case, since a leakage current (refer to symbol O) occurs through the sidewalls of the variable resistance material layer 11, there are difficulties in implementing a variable resistance memory device having a desired characteristic.
Furthermore, as the width W of the variable resistance material layer 11 decreases, it is advantageous in increasing an integration degree and securing a switching characteristic. In the case of ReRAM of which the resistance is changed by creation and destruction of a conductive filament, when the width W of the variable resistance material layer 11 is small, the creation and destruction of the conductive filament is controlled at a regular position. Therefore, a uniform switching characteristic may be secured. As described above, however, the variable resistance material layer 11 is patterned through an etch process. Therefore, there is a limitation in reducing the width W.